The court also heard there was a need to protect the confidentiality of documents provided to the ACCC by suppliers, and six supplier interview transcripts.

The issues relating to confidentiality for the sources of those documents are expected to be resolved in the next few weeks.

The legal action follows an investigation into media reports that emerged in 2011 that suppliers were facing undue pressure from Coles.

Around 50 suppliers came forward to speak confidentially to the ACCC.

The ACCC then used its compulsory information gathering powers, forcing suppliers and Coles to provide information about the claims.

Background to the court action

The ACCC alleges that, in 2011, Coles developed a strategy to improve its earnings by obtaining better trading terms from its suppliers.

It is alleged that one of the ways Coles sought to improve its earnings was through the introduction of ongoing rebates to be paid by its suppliers in connection with the Coles ARC program, based on purported benefits to large and small suppliers that Coles asserted had resulted from changes the supermarket had made to its supply chain.

The ACCC alleges Coles' target was to obtain $16 million in ARC rebates from smaller suppliers and was ultimately seeking an ongoing ARC rebate in the form of a percentage of the price it paid for the supplier's grocery products.

Coles continues to strongly deny the allegations.

"The aim of this program was to deliver cost savings to both Coles and suppliers and to improve product availability and enhance supply chain collaboration," the supermarket giant said in a statement.